what will I read if I have a signal with a frequencies of the order of 1GHz?

What will I read if I have a signal with a frequencies of the order of 1GHz on the digital input?
Do I get 1 if the time Average on the read period is greater than the threshold and 0 if less or I would just get the value of my signal at a specific point in time?

Thanks for the help!

How could a 16MHz microprocessor possibly read a 1 GHz signal?

You need a very expensive oscilloscope for that.

What is producing the 1GHz signal ?

...R

Maybe satellite lnb... :slight_smile:

Oh dear! :astonished:

You'll get what arrives at the pin at a controller clock edge. At 1GHz it's questionable what arrives at all, and what's swallowed by the connecing cable and input capacity.

At those kinds of frequencies you need to think RF, not just crude PCB traces and interconnecting wires.

Merely connecting to the Arduino could degrade the GHz signal by introducing stub antennas, impedance mismatches, and parasitic inductance and capacitance that will slur edges to the point an eye diagram would just look like a lava lamp.

What re you trying to do here? What is the source signal?

Thanks for the help!

for the same kind of input is it correct to assume I would get the time average if I used it as a analog read?

Blackfin:
At those kinds of frequencies you need to think RF, not just crude PCB traces and interconnecting wires.

Merely connecting to the Arduino could degrade the GHz signal by introducing stub antennas, impedance mismatches, and parasitic inductance and capacitance that will slur edges to the point an eye diagram would just look like a lava lamp.

What re you trying to do here? What is the source signal?

It is the product between two square waves.

I am mostly interested in knowing what the measurement that I will get mean

I am mostly interested in knowing what the measurement that I will get mean

Nothing.

What does the signal "mean"?

I have no idea what would happen. If the incoming data is digital and slightly-faster than you can read, you'd be randomly* sampling the ones & zeros and over the long term you'd get a proportional number of ones & zeros.

With too-fast digital data and analog read, you'd probably get something like an average based on the "duty cycle" (the high-to-low ratio).

If an analog signal exceeds half the sample rate (i.e. the Nyquist limit) you get aliasing (false frequencies) but a 1GHz nothing will be accurate, so who knows. A "normal" analog AC signal is positive half the time and negative half the time with an average of zero, but the Arduino can't read the negative half of an AC waveform. In fact it can be damaged by negative voltages.

  • It's not truly random but since the incoming data is and uncorrelated with the read timing it will appear to be random.

what device do you have that generates 5 volts peak to peak at 1 Ghz?
what is the capacitance of an Arduino input?
what strange conglomeration of cables and adapters would you use?